Internal combustion engine



1956 w. c. ESTES mma INTERNAL COMBUSTION ENGINE Filed May 2, 1955 INVENTOR. MLL/AM 6. Es res ,i zwzaandand ATTORNEYS United States Patent- INTERNAL COMBUSTION ENGINE William C. Estes, Redding, Calif. Application May 2, 1955, Serial No. 505,432

3 Claims. (Cl. 123-59) This invention relates to new and useful improvements in internal combustion enginesand in particular provides a simple means for supplying carbureted air to the combustion chamber of a cylinder in a two-cycle engine.

One object of this invention is to provide a fuel supplying means which is operated by and solely dependent on pressure differentials within the crankcase of the engine, thereby dispensing with unnecessary parts and separate power means.

Another object of this invention is to maintainfuel sepaj rate from the lubricating oil within the crank case, aifording efficient combustion and economy of operation.

It is also an object of this invention to provide an improved engine which may be utilized in both single and multiple-cylinder engines.

A further object is to space the said fuel supplying means from other working parts of the engine such that each part can work without interfering with the operation of another part.

This simple and reliable design and construction has particular application to two-cycle engines affording excellent economy and dependability of operation in such engines. The construction includes an auxiliary pressure regulator which prevents undue pressures within the crankcase and also maintains the said pressure diflerentials within a constant range.

The foregoing and other objects of this invention will appear from the following written description of one embodiment of the invention as illustrated in the accompanying drawings, wherein Fig. 1 is a side elevation of an internal combustion engine shown substantially in section and disclosing a preferred embodiment of the invention;

Fig. 2 is a side elevation shown partly in section of a three-cylinder engine taken at 90 degrees to Fig. l; and

Fig. 3 is a plan view of Fig. 2 shown on a smaller scale.

The engine comprises a closed crankcase 3 and a plurality of cylinder blocks 4 hermetically sealed thereto as by bolts 5.

For simplicity of illustration the engine is represented as being air-cooled, cooling fins 6 being provided for this purpose. g l

Each cylinder block 4 is provided at its'top with a spark plug 7, the igniting terminals (not illustrated) of which terminate inside the combustion chamber 8 of the cylinder 4. The cylinder is apertured at 9 and 11 to provide respectively intakeand exhaust ports. The said apertures or ports 9 and 11 are normally closed by the skirts of the piston 13, but are spaced downwardly from the top of the cylinder 4 a distance substantially equal to the stroke of the piston 13, such that the combustion chamber 8 can communicate with the exterior through the said ports only when the piston 13 is substantially at the bottom of its down stroke.

The crank case 3 is partitioned into separate units or compartments by walls or partitions 14 (Fig. 2) depending upon the number'of cylinders. Each partition 14 is in 2,773,489 Patented Dec. 11, 1956 substantially vertical alignment with the above separationbetween cylinders, and each partition is centrally aper tured and provided with a bearing 16. The crankshaft 17 able material such as neoprene which is not deleteriously aflected by fuel and oil. The dimension of the crankcase spaces the diaphragm 23 from the crankshaft 17 such that neither interferes with the operation of the other. A short cylinder 24 having an open end and a closed end and a diameter substantially equal to that of the said aperture in the crankcase 3 is secured at its open end in registry with aperture, and the peripheral edges of flexible diaphragm 23 are secured between the cylinder 24 and the crankcase 3. The closed end of the cylinder is centrally apertured to form an inlet 26, and a uni-directional valve such as a flap valve 27 is secured over the interior end of the said inlet. Secured to the exterior side of the closed end is a manifold 28 communicating with a carburetor 29. I

A mixture passage or vapor conduit 31 communicates with cylinder 24 with the inlet port 9 ofthe cylinder 4.

The pressure regulator comprises a pressure relief chamber 32 vented at its top and secured exteriorly to the crank case 3 by 1st and 2nd pipes or conduits 33 and 34. The said pipes individually communicate the pressure relief chamber 32 with the interior of the crank case 3. Both pipes 33 and 34 are preferably situated above the lubricating oil line (not illustrated) within the crank case 3. 1st pipe 33 is provided with an exhaust check valve 36 and terminates within the pressure relief chamber 32 adjacent the latters top; 2nd pipe 34 is provided with an intake check valve 37 and is upwardly bent to terminate in the bottom of the pressure relief chamber 32. The tension springs on the exhaust and intake check valves 36 and 37 are adjusted for the valves to open respectively at predetermined maximum desirable pressure and minimum desirable pressure, i. e., at maximum vacuum.

Operation On the down or power stroke the descending piston 13 compresses air within the crank case 3. The compressed air distends the diaphragm 23 outwardly or away from the crank case which causes valve 27 to close and compresses the carbureted air within the chamber 24 and communicating vapor conduit 31, which fuel has entered the chamber 24 as below described.

As the descending piston 13 uncovers the intake and exhaust ports 9 and 11 the exhaust gases escape through the exhaust ports 11, and the carbureted air, compressed in the vapor conduit 26, enters the combustion chamber 8 and is deflected upward, away from the descending exhaust gases.

Substantially simultaneously the pressure in the crank case 3 reaches a predetermined desirable maximum, overcoming the tension spring in'the exhaust check valve 36 and exhausting therethrough. The exhausted air escapes through the vent in the pressure relief chamber 32, and any lubricating oil which may have been exhausted drains to the bottom of the container to return to the crank case 3 through the inlet check valve 37.

Completing the cycle, on the upward stroke the rising piston 13 creates a partial vacuum within the crank case. The vacuum distends the diaphragm 23 inwardly 'or toward the crank case. This in turn creates a partial vacuum in the chamber 24, opening the flap valve 27 and drawing carbureted air therethrough. Near the top of the stroke the carbureted air which entered the combustion chamber on the down stroke is ignited by the spark plug 7, and substantially simultaneously the partial vacuum within the crank case reaches a. predetermined desirable minimum pressure, overcoming the tension spring on the intake check valve 37 and drawing air and any lubricating oil in the pressure relief chamber 32 into the crank case.

The cycle then repeats as above described.

It will thus be evident that the means supplying the fuel to the combustion chamber is exclusively dependent on pressure differentials within the crank case. Should a greater or lesser supply of fuel be desired per revolution, the intake check valve 36 may be adjusted to open respectively nearer or more distant in point of time from the peak of the stroke. Adjustment of the intake check. valve 36 determines the length of the period that the diaphragm 23 is distended toward the crank case, which in turn controls the flap valve 27 and quantity of carbureted air passed to the chamber 24 for supplying the combustion chamber 8. Additionally, the exhaust and check valves prevent harmful extremes of pressure within the crank case and consequent improper operation and damage to the diaphragm and other parts.

The diaphragm is spaced from the crankshaft such that neither interferes with the other and guards or other parts are unnecessary to protectthe diaphragm. Fuel and lubricating oil are at all times separate, facilitating efiiciency and economy of operation and economizing on oil consumption and reducing engine wear. Finally, the invention may be utilized equally satisfactorily on single or multiple-cylinder engines.

The foregoing description has been in some detail by way of illustration and example to augment clarity. It will be understood that certain changes and modifications may be made without departing from the spirit of the invention or scope of the appended claims.

I claim:

1. An internal combustion engine comprising a cylinder; a crank case; a crankshaft; a piston slidably mounted in the cylinder and working off the crankshaft; intake and exhaust ports located in the cylinder to permit communication from the interior of the cylinder to the exterior thereof only when the piston is substantially at its lowest stroke position; one wall of the crank case transverse. to the longitudinal axis of the crankshaft formed with an aperture, a flexible pressure responsive diaphragm sealing said aperture; a chamber formed interiorly of a housing secured on the exterior wall of said crank case; said diaphragm forming a portion of one wall of said chamber; valve means operable to admit carbureted air to said chamber; a conduit communicating the chamber with the intake port of said cylinder; a pressure relief chamber formed interiorly of a second housing; said second housing positioned exterior of the crank case with said chamber above the normal level of oil in said crank case; said chamber vented to the atmosphere adjacent the top portion of said second housing; a first pipe communicating with said crank case at a point substantially above the oil level in said crank case and connected to said relief chamber in fluid communication therewith at a point substantially above the bottom of said relief chamber; a second pipe communicating with said crank case and connecting with said relief chamber in fluid communication at a point substantially below the point of connection of said first pipe with said relief chamber; said first pipe provided with a check valve adjusted to open when the pressure in the crank case reaches a predetermined maximum; and said second pipe provided with a check valve adjusted to open when the pressure in the crank case falls below a predetermined minimum.

2. An internal combustion engine comprising a plurality of cylinders disposed in a single row; a crank case divided into separate pressure compartments by wallsreach said compartment aligned with one said cylinder; a com mon crankshaft disposed within each said compartment; a piston slidably mounted in each cylinder and working off the crankshaft; intake and exhaust ports located in each of the cylinders to permit communication from the interior of the cylinders to theexterior only when the pistons are substantially at their lowest stroke position; each compartment of said crank case formed with an aperture; each said aperture disposed on the side of said crank case transverse to the longitudinal axis of the crankshaft; a flexible pressure responsive diaphragm sealing each said aperture; housing members. forming the walls of a plurality of chambers secured on the exterior wall of said crank case and aligned with each said compartment; a portion of one wall of each said chamber comprising a said diaphragm; valve means operable to admit carbureted air into each said chamber and a conduit connecting each said chamber in fluid, communication with the intake port of the cylinder aligned therewith.

3. An internal combustion engine comprising a plurality of cylinders disposed in a single row; a crank case divided into separate pressure compartments by walls; each said compartment aligned with one said cylinder; 21 common crankshaft disposed within each said compartment; a piston slidably mounted in each cylinder and working off the crankshaft; intake and exhaust ports located in each of the cylinders to permit communication from the interior of the cylinders to the exterior only when the pistons are substantially at their lowest stroke position; each compartment of said crank case formed with an aperture; each said aperture disposed on the side of said crank case transverse to the longitudinal axis of the crankshaft; a flexible pressure responsive diapragrn sealing. each said aperture; housing members forming the walls of a plurality of chambers secured on the exterior wall of said crank case and aligned with each said compartment; a portion of one wall of each said chamber comprising a diaphragm;

valve means operable to admit carbureted air into each saidtchamberra, conduit connecting each said chamber in fluid communication with the intake port of the cylinder aligned therewith, a plurality of pressure relief chambers formed by walls positioned exteriorly of the crank case with the chambers disposed above the normal levelof oil within the said crank case; each chamber formed with a vent to the atmosphere proximate the top wall of said chamber; a plurality of first pipes with each said pipe connected with said crank case in fluid communication with one compartment at a point substantially above the oil level within the compartment and joining the compartment. infiuid communication with a relief chamber at a point near the top wall of the relief chamber; a plurality of second pipes each connected with said crank case communicating in fluid communication with a compartment of said crank case and joining the compartment in fluid communication with a relief chamber at a point substantially below the point of connection of said first pipe; a check valve for each first pipe with each valve adjusted to, open fluid communication through the first pipe when pressure in a compartment reaches a predetermined max imum and a second check valve for each second pipe with each second check valve adjusted to open fluid communication through the second pipe when the pressure in a compartment falls below a predetermined minimum.

References Cited in thefile of this patent UNITED STATES PATENTS 861,711 Croft July 30, 1907 1,301,485 Mueller Apr. 22, 1919 FOREIGN PATENTS 81,216 Austria 0-, Aug. 25, 1920 

